UNIT A CHAPTER 3 REVIEW

When you hold your breath, your brain sends a message to the diaphragm and rib muscles telling them to breathe. Why is this message sent from the brain?

because carbon dioxide is building up in the blood.

Which type of blood vessel takes blood from the cells back to the heart?

vein

Around the wall of each air sac in the lungs is a web of …

capillaries

When does digestion begin?

when the teeth grind the food

How does food move through the esophagus?

Rings of muscles squeeze food down the esophagus.

Which organs send chemicals to the small intestine to help

digest food?

pancreas and liver

What is the role of villi in the small intestine?

The villi provide more surface area to absorb food.

The transportation system of the body is …

circulatory system

Which system in the human body is involved in removing

wastes from the body?a. urinaryb. nervousc. skeletald. circulatory

urinary

Name three tasks the kidneys perform.

1. Clean the blood2. Regulate the level of salt in the

blood3. Control the level of water in

the blood

Which organ stores a mix of wastes and water until the mix of waste and water is ready to leave the body?

Urinary bladder

Which type of cell will the body make in greater numbers in response to an infection?

white blood cells

What is the thick, sticky fluid that traps germs and other things that may be in the air?

mucus

Which part of your blood has the job of clotting your blood?

platelets